Harmonic control, in particular in permanent magnet generators, may be required in order to control noise and vibration as well as to increase system efficiency. Harmonic control may in particular be applied to direct drive generators which do not have a gearbox in the drive train. Conventionally, a fundamental current controller and a harmonic current controller may be utilized in a vector controlled drive. Conventionally, a high control effort, poor dynamic performance, instability and inaccurate speed/position estimation has been observed to be present.
Conventionally, digital filters have been added to the current feedbacks, the bandwidth of the fundamental current control has been reduced and digital filters have been added to the voltage references used as inputs to a speed observer. Thereby, the control effort of the harmonic current controller may be reduced, the harmonic current controller dynamic performance may be improved and speed/position estimation may be improved regarding the accuracy. However, some major drawbacks are concurrently observed: (1) The introduction of filters may tend to undermine the system stability, thereby reducing stability margins; (2) reduction of the fundamental current controller bandwidth may reduce its dynamic performance and may negatively affect outer control loops.
Thus, there may be a need for an arrangement and for a method for determining an operation parameter reference for controlling a generator side converter portion coupled to a generator, wherein at least some of the above-mentioned issues are addressed, wherein in particular a simple solution having sufficient system stability is achieved.